U.S. patent application number 10/405976 was filed with the patent office on 2004-04-22 for arrangement for and method of monitoring, calibrating and optimizing a control of an electromedical implant.
This patent application is currently assigned to Biotronik Mess-und Therapiegeraete GmbH & Co.. Invention is credited to Czygan, Gerald, Schaldach, Max, Schaldach, Max JR..
Application Number | 20040078061 10/405976 |
Document ID | / |
Family ID | 28051282 |
Filed Date | 2004-04-22 |
United States Patent
Application |
20040078061 |
Kind Code |
A1 |
Czygan, Gerald ; et
al. |
April 22, 2004 |
Arrangement for and method of monitoring, calibrating and
optimizing a control of an electromedical implant
Abstract
The invention concerns an arrangement (10) for and an associated
method of monitoring and adjusting a control of an electromedical
implant (12) for intracardial cardiac therapy by means of an
external control and evaluation unit (14). The arrangement (10)
includes: (a) the electromedical implant (12) which includes the
following components: a clock and timer unit (40) for the
co-ordination of a time sequence of control operations, an energy
source for providing an operating voltage and stimulation and shock
delivery, at least one electrode (38) which is connected to the
myocardium of the heart and which is suitable for the delivery of
electrical pulses, a sensor means (28) which supplies measurement
data about physiological parameters in the region of the heart and
about internal status parameters of the implant, a memory unit (34)
for the storage of internal control sequences (SS.sub.in), control
parameters (SP) and measurement data of the sensor means (28), a
telemetry unit (16) having a transmitter (24) and a receiver (20)
for bidirectional data exchange with the external control and
evaluation unit (14), and a central, autarchically runnable control
logic means (30) which on the basis of the internal control
sequences (SS.sub.in) and control parameters (SP) controls the
activities of the at least one electrode (28), the telemetry unit
(16), the sensor means (28) and the memory unit (34), and (b) the
external control and evaluation unit (14) which includes the
following components: a telemetry unit (18) having a transmitter
(22) and a receiver (26) for bidirectional data exchange with the
electromedical implant (12), a clock and timer unit (42) for the
co-ordination of a time sequence of control operations, an energy
source for providing an operating voltage, a memory unit (36) for
storing control sequences (SS), control parameters (SP) and
communicated data (D.sub.im) of the implant (12), and a central,
autarchically runnable evaluation logic means (32) which controls
the activities of the telemetry unit (18) and the memory unit (36),
which is in contact with the clock and timer unit (42) and which on
the basis of the communicated data (D.sub.im) ascertains control
sequences and control parameters (SS, SP) for monitoring and
adjusting the implant (12) and co-ordinates the transmission
thereof to the implant (12).
Inventors: |
Czygan, Gerald; (Buckenhof,
DE) ; Schaldach, Max; (Erlangen, DE) ;
Schaldach, Max JR.; (Berlin, DE) |
Correspondence
Address: |
HAHN LOESER & PARKS, LLP
TWIN OAKS ESTATE
1225 W. MARKET STREET
AKRON
OH
44313
US
|
Assignee: |
Biotronik Mess-und Therapiegeraete
GmbH & Co.
|
Family ID: |
28051282 |
Appl. No.: |
10/405976 |
Filed: |
April 2, 2003 |
Current U.S.
Class: |
607/32 |
Current CPC
Class: |
A61N 1/37252 20130101;
A61N 1/37211 20130101 |
Class at
Publication: |
607/032 |
International
Class: |
A61N 001/362 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 5, 2002 |
DE |
102 16 216.6 |
Claims
1. An arrangement (10) for monitoring and adjusting a control of an
electromedical implant (12) for intracardial cardiac therapy by
means of an external control and evaluation unit (14) in which (a)
the electromedical implant (12) includes the following components:
a clock and timer unit (40) for the co-ordination of a time
sequence of control operations, an energy source for providing an
operating voltage and stimulation and shock delivery, at least one
electrode (38) which is connected to the myocardium of the heart
and which is suitable for the delivery of electrical pulses, a
sensor means (28) which supplies measurement data about
physiological parameters in the region of the heart and about
internal status parameters of the implant, a memory unit (34) for
the storage of internal control sequences (SS.sub.in), control
parameters (SP) and measurement data of the sensor means (28), a
telemetry unit (16) having a transmitter (24) and a receiver (20)
for bidirectional data exchange with the external control and
evaluation unit (14), and a central, autarchically runnable control
logic means (30) which on the basis of the internal control
sequences (SS.sub.in) and control parameters (SP) controls the
activities of the at least one electrode (28), the telemetry unit
(16), the sensor means (28) and the memory unit (34), and (b) the
external control and evaluation unit (14) includes the following
components: a telemetry unit (18) having a transmitter (22) and a
receiver (26) for bidirectional data exchange with the
electromedical implant (12), a clock and timer unit (42) for the
co-ordination of a time sequence of control operations, an energy
source for providing an operating voltage, a memory unit (36) for
storing control sequences (SS), control parameters (SP) and
communicated data (D.sub.im) of the implant (12), and a central,
autarchically runnable evaluation logic means (32) which controls
the activities of the telemetry unit (18) and the memory unit (36),
which is connected to the clock and timer unit (42) and which on
the basis of the communicated data (D.sub.im) ascertains control
sequences and control parameters (SS, SP) for monitoring and
adjusting the implant (12) and co-ordinates the transmission
thereof to the implant (12).
2. An arrangement as set forth in claim 1 characterized in that the
evaluation logic means (32) includes an expert system (ES) which is
adapted to assess all monitoring and adjusting tasks for the
intracardial cardiac therapy on a patient-individual basis and
divides the control sequences (SS) on which the monitoring and
adjusting tasks are based into internal control sequences
(SS.sub.in) for the implant (12) and external control sequences
(SS.sub.ex) for the external evaluation and control unit (14).
3. An arrangement as set forth in claim 2 characterized in that the
internal control sequences (SS.sub.in) include the therapy and
diagnostic sequences which are absolutely necessary for controlling
the therapy functions or diagnosis of given cardiac events
respectively.
4. An arrangement as set forth in claim 2 characterized in that the
internal control sequences (SS.sub.in) include real time-dependent
stimulation and diagnostic sequences.
5. An arrangement as set forth in one or more of claims 1 through 4
characterized in that the external control and evaluation unit (14)
includes a first input unit (44) for interaction with the patient,
by way of which the patient can input controls values (SG) and
influence the evaluation logic means (32) or can implement markings
and assessments of given states or symptoms.
6. An arrangement as set forth in one or more of claims 1 through 5
characterized in that the external control and evaluation unit (14)
includes a second input unit (46) for data exchange with further
peripheral devices, by way of which control values (SG) can be
inputted, control sequences (SS) for the evaluation logic means
(32) can be modified or produced afresh and/or data can be read out
of the memory unit (36) for additional evaluation.
7. An arrangement as set forth in one or more of claims 1 through 6
characterized in that the external control and evaluation unit (14)
includes a further input unit (45) for data exchange with external
sensors, by way of which control values (SG) can be inputted.
8. An arrangement as set forth in one or more of claims 1 through 7
characterized in that the external control and evaluation unit (14)
includes a further input unit (47) with integrated sensors, by way
of which control values (SG) can be inputted.
9. An arrangement as set forth in one or more of claims 1 through 8
characterized in that the evaluation logic means (32) of the
external control and evaluation unit (14) has a memory (48) for a
complex matrix into which at least the transmitted data (D.sub.im)
of the implant (12) and the control values (SG) pass and which
delivers the control parameters (SP) and control sequences (SS) on
which the monitoring and adjusting tasks are based.
10. An arrangement as set forth in claim 9 characterized in that
the evaluation logic means (32) is such that the control parameters
(SP) and/or control sequences (SS) which are provided for the
telemetric data exchange are interlinked with weighting factors
(G.sub.i), on the basis of which a time progression (t.sub.int)
and/or a series (R) of transmission of the individual monitoring
and adjusting tasks is established in an interaction scheme
(50).
11. A method of monitoring and adjusting a control of an
electromedical implant (12) for intracardial cardiac therapy by
means of an external control and evaluation unit (14), wherein (a)
in the electromedical implant (12) a time sequence of the control
operations is co-ordinated by a clock and timer unit (40),
electrical pulses are delivered by way of at least one electrode
(38) connected to the myocardium of the heart, measurement data
relating to physiological parameters in the region of the heart and
internal status parameters of the implant (12) are supplied by a
sensor means (28), internal control sequences (SS.sub.int), control
parameters (SP) and measurement data of the sensor means are stored
in a memory unit (34), data are exchanged with the external control
and evaluation unit (14) by way of a bidirectional telemetry unit
(16), and the activities of the at least one electrode (38), the
telemetry unit (16), the sensor means (28) and the memory unit (34)
are co-ordinated on the basis of the internal control sequences
(SS.sub.in) and control parameters (SP) in a central autarchically
runnable control logic means (30), and (b) in the external control
and evaluation unit (14) data are exchanged by way of a
bidirectional telemetry unit (18) with the electromedical implant
(12), a time sequence of the control operations is co-ordinated by
a timer unit (42), control sequences (SS), control parameters (SP)
and communicated data (D.sub.im) of the implant (12) are stored in
a memory unit (36), and in a central autarchically runnable
evaluation logic means (32) the activities of the telemetry unit
(18) and the memory unit (36) are controlled and on the basis of
the communicated data (D.sub.im) control sequences and control
parameters (SS, SP) for monitoring and adjusting the implant (12)
are ascertained and the transmission thereof to the implant (12) is
co-ordinated.
12. A method as set forth in claim 11 characterized in that the
evaluation logic means (32) of the external control and evaluation
unit (14) includes a memory (48) for a complex matrix into which at
least the transmitted data (D.sub.im) of the implant (12) and the
control values (SG) pass and which delivers the control parameters
(SP) and control sequences (SS) on which the monitoring and
adjusting tasks are based.
13. A method as set forth in claim 12 characterized in that the
control values (SG) include time-dependent control values
(SG.sub.t).
14. A method as set forth in claim 13 characterized in that the
time-dependent control values (SG.sub.t) include a factor which
compels routine checking of the entire control of the implant (12)
or sub-regions of said control at predeterminable time
intervals.
15. A method as set forth in claim 13 characterized in that the
time-dependent control values (SG.sub.t) include a factor which can
be inputted by the patient by way of a first input unit (44) at the
external control and evaluation unit (14) and compels routine
checking of the entire control of the implant (12) or sub-regions
of the control at predeterminable time intervals.
16. A method as set forth in claim 13 characterized in that the
time-dependent control values (SG.sub.t) include a factor which can
be predetermined by way of a second input unit (46) at the external
control and evaluation unit (14) by means of suitable peripheral
devices and compels routine checking of the entire control of the
implant (12) or sub-regions of the control.
17. A method as set forth in one of claims 10 through 14
characterized in that the control values (SG) include
event-dependent control values (SG.sub.ev).
18. A method as set forth in claim 17 characterized in that the
event-dependent control values (SG.sub.ev) include a factor which
can be inputted by way of the first input unit (44) at the external
control and evaluation unit (14) by the patient, passes into the
evaluation, and compels monitoring or adjustment of the entire
control of the implant (12) or sub-regions of the control at
predeterminable time intervals.
19. A method as set forth in claim 17 characterized in that the
event-dependent control values (SG.sub.ev) include a factor which
can be predetermined by way of the second input unit (46) at the
external control and evaluation unit (14) by means of suitable
peripheral devices, passes into the evaluation and compels
monitoring or adjustment of the entire control of the implant (12)
or sub-regions of the control at predeterminable time
intervals.
20. A method as set forth in claim 17 characterized in that the
event-dependent control values (SG.sub.ev) include a factor which
can be predetermined by way of the further input units (45, 47) at
the external control and evaluation unit (14) with integrated or
external sensors, passes into the evaluation and compels monitoring
or adjustment of the entire control of the implant (12) or
sub-regions of the control at predeterminable time intervals.
21. A method as set forth in one or more of claims 11 through 20
characterized in that the control parameters (SP) and control
sequences (SS) are interlinked with weighting factors (G.sub.i), on
the basis of which a time progression of the individual monitoring
and adjusting tasks is established in an interaction scheme
(50).
22. A method as set forth in claim 21 characterized in that the
weighting factors (G.sub.i) serve to establish a series (R) of the
monitoring and adjusting tasks which are transmitted during the
interaction of the external control and evaluation unit (14) to the
implant (12).
23. A method as set forth in claim 21 or claim 22 characterized in
that in the normal situation the weighting factors (G.sub.i) are so
predetermined that the impending monitoring and adjusting tasks are
carried out in a rest phase of the patient.
24. A method as set forth in claim 21 or claim 22 characterized in
that in the acute situation the weighting factors (G.sub.i) are so
predetermined that the impending monitoring and adjusting tasks
begin immediately after production of the interaction scheme
(50).
25. An external evaluation and control unit (14) for an arrangement
(10) as set forth in one or more of claims 1 through 10 and for
carrying out a method as set forth in one or more of claims 11
through 24.
Description
[0001] The invention concerns an arrangement for monitoring and
adjusting a control of an electromedical implant for intracardial
cardiac therapy by means of an external control and evaluation unit
having the features of claim 1, an associated method having the
features of claim 9 and the external control and evaluation unit
itself as set forth in claim 22.
BACKGROUND OF THE ART
[0002] Electromedical implants such as cardiac pacemakers and
defibrillators have proven to be an extraordinarily successful
instrument for the electrotherapy of bradycardiac and tachycardiac
rhythm disturbances. In that respect the task of implants of that
kind is not restricted just to merely delivering electrical pulses
to the atrium or ventricle myocardium in order there to trigger off
depolarization. Rather, modern pacemakers and defibrillators
involve sensors and evaluation circuits which permit controlled or
regulated frequency adaptation, adaptation of pulse amplitude,
pulse width and AV-time for therapy optimization purposes. In that
way the aim is for the cardiovascular system of the patient to be
modeled as closely as possible on the natural regulating mechanism,
in terms of its reaction to physical or psychic loading (frequency-
or rate-adaptive cardiac pacemaker).
[0003] Electromedical implants at the present time involve a
modular design for achieving that aim. Such an implant generally
includes elements such as a central control logic, a sensor
arrangement for detecting body functions and for intracardial
signal recording in the myocardium of the right atrium or
ventricle, electrodes anchored in the myocardium, including a
circuit for regulating pulse delivery, an energy source for the
operating voltage, and a clock and timer unit. It will be
appreciated that the specified individual components can be adapted
variably to a high degree in respect of their design configuration
to the respective conditions prevailing. Therefore the individual
components and the appropriate combinations thereof will not be
described in detail here as they are known.
[0004] Just for reasons relating to circuitry engineering it has
been found appropriate for the functions of the implant to be
limited to control of the pulse delivery and intracardial signal
recording. More extensive tasks such as for example monitoring and
optimizing the control itself can generally only be implemented to
a very limited degree. That is not only due to the fact that the
implementation of such complex control circuits in the limited
structural space of the implant encounters at the present time the
viable limits thereof. Rather, such a complex control circuit would
also result in a markedly increased level of energy consumption so
that the service life of the implant would be curtailed. Also, in
general a defective control logic system cannot check and re-set
itself. For those reasons it has been found appropriate for the
electromedical implant and also an external programming device each
to be provided with a transmitter and receiver. The telemetry units
of the two components provides for the execution of bidirectional
data exchange which includes stimulation and diagnostic parameters
or recorded intracardial signal and operating parameters
respectively.
[0005] U.S. Pat. No. 4,705,043 to Imran shows by way of example
such an external programming device which provides for evaluation
of the transmitted intracardial signals and communicates
stimulation parameters to the implant. A disadvantage here is that
the external electrical stimulator is an essential part of the
control of the implant and, in the event of failure thereof, the
implant can continue to operate at best in a predetermined basic
configuration.
[0006] DE 37 22 829 C2 describes a method in which an implantable
electromedical device can communicate with an external programming
device, with the transmission of encoded signals. The external
programming device generally comes temporarily into contact with
the implant, in which case the operating mode and parameters which
determine pulse triggering are communicated to an internal
programming part of the implant or modified. In that arrangement
the external programming device is so designed that it does not
communicate with the implant independently but rather only after a
given task has been predetermined for it by the programmer
(generally the doctor). In practice such programming devices are
correspondingly simplified in respect of their technical structure.
They essentially consist of the transmitting and receiving unit and
numerous interfaces, by way of which peripheral units can be
connected. There is no provision for autarchical control.
Accordingly the patient has to stay in the clinic in the procedure
involving programming, optimization and implementation of an
exercise stress test, in which respect he is additionally impeded
by extensive cabling. As is known, the unusual surroundings result
in what is referred to as the white coat effect in which the
cardiovascular system of the patient is precisely not subject to
everyday conditions and thus optimization of the stimulation effect
is made difficult or entirely prevented.
SUMMARY OF THE INVENTION
[0007] Therefore the object of the present invention is to provide
an arrangement for and a method of monitoring and adjusting the
control of the electromedical implant for intracardial cardiac
therapy with which the mobility of the patient is substantially
improved. Along with that the invention seeks to improve in
particular optimization of the control parameters on the basis of
intracardial signals recorded under everyday conditions. The system
is to operate as independently as possible and is to be capable of
reacting flexibly to the possibly altered conditions without the
patient having to submit to time-consuming clinical
investigations.
[0008] That object is attained by the arrangement according to the
invention for monitoring and adjusting a control of an
electromedical implant for intracardial cardiac therapy by means of
an external control and evaluation unit having the features of
claim 1, and the associated method having the features of claim 9.
The arrangement includes:
[0009] (a) the electromedical implant which includes the following
components:
[0010] a clock and timer unit for the co-ordination of a time
sequence of control operations,
[0011] an energy source for providing an operating voltage and
stimulation and shock delivery,
[0012] at least one electrode which is connected to the myocardium
of the heart and which is suitable for the delivery of electrical
pulses,
[0013] a sensor means which supplies measurement data about
physiological parameters in the region of the heart and about
internal status parameters of the implant,
[0014] a memory unit for the storage of internal control sequences,
control parameters and measurement data of the sensor means,
[0015] a telemetry unit having a transmitter and a receiver for the
bidirectional data exchange with the external control and
evaluation unit, and
[0016] a central, autarchically runnable control logic means which
on the basis of the internal control sequences and control
parameters controls the activities of the at least one electrode,
the telemetry unit, the sensor means and the memory unit, and
[0017] (b) the external control and evaluation unit which includes
the following components:
[0018] a telemetry unit having a transmitter and a receiver for the
bidirectional data exchange with the electromedical implant,
[0019] a timer unit for the co-ordination of a time sequence of
control operations,
[0020] an energy source for providing an operating voltage,
[0021] a memory unit for storing control sequences, control
parameters and communicated data of the implant, and
[0022] a central, autarchically runnable evaluation logic means
which controls the activities of the telemetry unit and the memory
unit, which is in contact with the clock and timer unit and which
on the basis of the communicated data ascertains control sequences
and control parameters for monitoring and adjusting the implant and
co-ordinates the transmission thereof to the implant.
[0023] The autarchically runnable control logic means of the
implant firstly ensures comfortable everyday operation so that the
implant and the external control and evaluation unit do not have to
be permanently in telemetric contact. The control and evaluation
unit with its autarchically runnable evaluation logic means
contains sequences which permit very much more extensive evaluation
and optimization of the control.
[0024] In accordance with the method:
[0025] (a) in the electromedical implant
[0026] a time sequence of the control operations is co-ordinated by
a clock and timer unit,
[0027] electrical pulses are delivered by way of at least one
electrode connected to the myocardium of the heart,
[0028] measurement data relating to physiological parameters in the
region of the heart and internal status parameters of the implant
are supplied by a sensor means,
[0029] internal control sequences, control parameters and
measurement data of the sensor means are stored in a memory
unit,
[0030] data are exchanged with the external control and evaluation
unit by way of a bidirectional telemetry unit, and
[0031] the activities of the at least one electrode, the telemetry
unit, the sensor means and the memory unit are co-ordinated on the
basis of internal control sequences and control parameters in a
central autarchically runnable control logic means, and
[0032] (b) in the external control and evaluation unit
[0033] a time sequence of the control operations is co-ordinated in
a timer unit,
[0034] data are exchanged by way of a bidirectional telemetry unit
with the electromedical implant,
[0035] control sequences, control parameters and communicated data
of the implant are stored in a memory unit, and
[0036] in a central autarchically runnable evaluation logic means
the activities of the telemetry unit and the memory unit are
controlled and on the basis of the communicated data control
sequences and control parameters for monitoring and adjusting the
implant are ascertained and the transmission thereof to the implant
is co-ordinated.
[0037] In a preferred embodiment of the invention the arrangement
includes an expert system which assesses on an individual patient
basis all monitoring and adjusting tasks for intracardial cardiac
therapy and divides the control sequences on which the monitoring
and adjusting tasks are based into internal control sequences for
the implant and external control sequences for the external
evaluation and control unit. The aim of that division is to make
the implant admittedly substantially autarchically operable for
everyday conditions, but to cause tasks beyond that, in diagnosis
and therapy, to be implemented only by way of the evaluation and
control unit. Sequences which in accordance with the present
patient image appear unnecessary or which are only associated with
general monitoring of the operating status of the implant should if
possible not be stored in the implant itself. Preferably, only the
internal control sequences which include functional and diagnostic
parameters which are absolutely necessary for control of the
therapy functions or the diagnosis of given cardiac events remain
in the implant. They also preferably include real time-dependent
stimulation and diagnostic sequences. Overall therefore the control
complication in the implant is to be reduced, which ultimately
results in an energy saving and thus an increase in the service
life.
[0038] It is further preferable if the evaluation logic means of
the external control and evaluation unit has a memory for a complex
matrix into which at least the communicated data of the implant and
further control parameters pass. By means of such a matrix it is
possible speedily to ascertain the control parameters and control
sequences on which the monitoring and adjusting tasks are
based.
[0039] In a preferred embodiment of the concept of the invention
the control and evaluation unit includes a first input unit for
interaction with the patient. By way of that input unit the patient
can input control parameters which have an influence on the
operation of ascertaining the control sequences and parameters in
the evaluation logic means and thus indirectly on control of the
implant. That for the first time permits the patient to play a more
active part in adjusting and checking the diagnostic and
stimulation parameters, which obviously can be limited by suitable
programming to given regions/action of the control logic means of
the implant. It is also possible that input can be effected by way
of the first input unit in various stages. Besides the possibility
of directly intervening in the control, there should be a pure
marker function. The patient can merely document or assess given
statuses or symptoms for example by pressing a button.
[0040] It is further preferable for the external control and
evaluation unit to have a second input unit for data exchange with
further peripheral devices. Control sequences for the evaluation
logic means can be set up or modified and/or data can be read out
of the memory unit for additional evaluation, by way of that second
input unit. Conversely, time-dependent or event-dependent control
parameters of the matrix can be communicated in that way. It should
be emphasized at this point that the patient no longer necessarily
has to be present on the spot (generally in the clinic) for such a
data exchange, but it is only necessary for the external control
and evaluation unit to be connected to the peripheral devices. Data
exchange can then take place in particular on-line by way of a
telephone connection.
[0041] In a further preferred embodiment of the invention the
control parameters and control sequences ascertained by the matrix
are linked with weighting factors. A time sequence of the
individual monitoring and adjusting tasks is established in an
interaction scheme on the basis of the weighting factors. Thus for
example a time interval up to the initiation of the next routine
checks can be reduced in length if the evaluation of the last
measurements has furnished significant deviations from the
medically necessary stimulation behavior. The external control and
evaluation unit has a clock and timer unit for time co-ordination
of the data exchange.
[0042] In the normal situation the weighting factors are
predetermined in such a way that the impending monitoring and
adjusting tasks preferably take place when the patient is in a rest
phase. In that way disturbances in the course of everyday life of
the patient as a consequence of extensive changes in the
stimulation and diagnostic parameters are to be minimized. In the
acute situation, for example if the stimulation parameters deviate
substantially from the medically necessary pulse deliveries data
exchange begins immediately after the interaction scheme has been
prepared. It will be appreciated that the procedure for
optimization of control of the implant can be effected on-line with
the external control and evaluation unit, that is to say data
exchange can take place one after the other until optimum
conditions obtain. Preferably also a series of the control
parameters and control sequences communicated to the implant during
the interaction of the external control and evaluation unit is
established by the weighting factors. In that way for example
optimization of the stimulation parameters, which is more
significant for the patient, can be preferred to routine checking
of the implant.
[0043] An external evaluation and control unit which is modified in
the above-indicated manner is claimed separately.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] Further preferred configurations of the invention are set
forth by the other features recited in the appendant claims. The
invention is described in greater detail hereinafter in an
embodiment by way of example with reference to drawings in
which:
[0045] FIG. 1 is diagrammatic view showing the principle involved
in relation to the mode of operation of an arrangement for
monitoring and adjusting a control of an electromedical implant for
intracardial cardiac therapy by an external control and evaluation
unit, and
[0046] FIG. 2 shows a functional block circuit diagram of an
evaluation logic means of the external control and evaluation
unit.
DETAILED DESCRIPTION OF THE INVENTION
[0047] FIG. 1 shows the structure in principle of an arrangement 10
for monitoring and adjusting a control of an electromedical implant
12 for intracardial cardiac therapy by an external control and
evaluation unit 14. The electromedical implant 12 is for example a
rate-adaptive cardiac pacemaker.
[0048] The implant 12 and the control and evaluation unit 14 each
include a telemetry unit 16, 18 with a respective transmitter 20,
22 and receiver 24, 26, which are suitable for the bidirectional
telemetric transmission of data. The data transmitted
telemetrically contain for example items of patient information
such as the implantation date, the date of the last aftercare,
details relating to the symptoms and so forth. In addition
diagnostic information, for example relating to atrial or
ventricular diagnosis and stimulation can be communicated. In
addition battery and electrode parameters, in particular the
currently prevailing values of battery voltage, internal battery
resistance and current consumption are transmitted in order to
permit a realistic estimate of the operating time to be expected.
Furthermore measurement data which is discussed in greater detail
hereinafter from a sensor means 28 and control sequences and
parameters for a control logic means 30 of the implant 12 and
evaluation logic means 32 of the evaluation and control unit 14 can
be exchanged by way of the telemetry units 16, 18. The structure
and mode of operation of such telemetry units 16, 18 have long been
known from the state of the art and are therefore not to be
discussed in greater detail at this point.
[0049] The implant 12 further includes a sensor means 28 with which
parameters of physical or physiological nature which can be used
for controlling or regulating the therapy can be directly detected.
Examples in that respect are piezoelectric oscillators or
capacitive sensors for detecting body activity and kinetic energy,
sensors for detecting a central-venous blood temperature or oxygen
saturation, pH-value sensors, sensors for detecting a respiration
rate, a respiration minute volume and the beat volume of the heart,
sensors for determining contractibility or contraction dynamics and
sensors for detecting evoked myocardium potentials. In this case
also the sensor means 28 will not be described in greater detail as
they have already long been known from the state of the art.
[0050] Both the implant 12 and also the control and evaluation unit
14 include a memory unit 34, 36. The memory unit 34 of the implant
12 serves for the storage of internal control sequences, control
parameters and measurement data of the sensor means 28 and the
memory unit 36 of the control and evaluation unit 14 serves for the
storage of control sequences, control parameters and transmitted
data.
[0051] The implant 12 has an electrode 38 for stimulation and
diagnostic purposes. The electrode 38 is connected to the
myocardium of the heart and is suitable for the delivery of
electrical pulses. In principle it is possible to use any electrode
known from the state of the art if it can be employed for the
stimulation and diagnostic tasks to be performed. In addition the
implant 12 has an energy source (not shown here) for providing the
operating voltage (generally a battery).
[0052] The implant 12 includes a suitable circuit with which it is
possible to implement the control logic means 30 which co-ordinates
the activities of all the system components present in regard to
stimulation and diagnosis on the basis of internal control
sequences and control parameters. The control logic means is
autarchically runnable, that is to say on its own it can ensure all
the stimulation and diagnostic tasks relating to everyday life. A
central control logic means 30 of that kind is usually an
integrated semiconductor circuit connected to other system
components, in particular the means for telemetry as indicated at
16, 18, sensor means 28, memory means 34, 36 and the electrode
actuation means. Attention is again directed here to the numerous
design configurations described in the state of the art. The
functional components of the control logic means 30, which serve to
carry the invention into effect, are in practice implemented in the
form of software and are inseparably interwoven with the rest of
the pacemaker structure.
[0053] For a cardiac pacemaker which has at least one electrode 38
for pulse excitation and diagnosis in the right atrium and
ventricle, the individual tasks of the pacemaker control logic
means 30 can be implemented in the form of a binary automatic
device which can assume different states in dependence on given
time intervals and detected signals. The most important time
intervals for the control procedure relate for example to periods
of time which can pass at a maximum between two natural pulses of
the respective chambers without a stimulus being triggered. An
AV-delay is shortened in modern pacemakers on the one hand after
detected events in relation to stimulated events in order to take
account of the delay between atrium stimulus and actual atrium
depolarization (latency time compensation). On the other hand the
AV-delay is shortened in dependence on frequency to simulate a
natural dromotrophy in order to ensure optimum synchronization even
at higher heart rates (dynamic AV-time). In regard to details
relating to such a control logic means 30 attention is directed to
the book by Schaldach, Electrotherapy of the Heart, Springer
Verlag, Berlin, 1992. It will be self-evident that a clock and
timer unit 40 must be provided for the implementation of a control
logic means 30 of that kind. The clock and timer unit 40 is for
example an oscillator quartz. A clock and timer unit 42 is also
required on the part of the external control and evaluation unit 14
for time co-ordination of the control procedures.
[0054] The external control and evaluation unit 14 further includes
two input units 44, 46. The first input unit 44 is intended to
permit interaction on the part of the patient. That is intended to
provide that the patient can appropriately react to physical
hardships which possibly occur and can influence control of the
implant 12. In that respect, an extent of the intervention options
can be defined by the evaluation logic means 32, in dependence on
the individual skills of the patient. It is also possible for the
input to be effected in various stages by way of the first input
unit 44. A pure marker function should be possible, besides the
direct option of intervention in the control arrangement. The
patient can merely document or assess given symptoms or states for
example by pressing a button.
[0055] The second input unit 46 is intended to permit data exchange
with further peripheral devices. If for example extensive
statistical evaluations involving a high level of computing
expenditure are to be carried out or if data put into intermediate
storage in the control and evaluation unit 14 are to be fed to an
output device, a communication with those peripheral devices can be
effected by way of the second input unit 46. In the reverse
direction, the control sequences and control parameters of the
evaluation logic means 32 itself can be adapted to new requirements
and can possibly be completely set up afresh. The second input unit
46 can in particular include a modem for connection to a telephone
line so that remote maintenance of the evaluation and control
device 14 is possible.
[0056] A further input unit 45 is provided for the connection of
external sensors to the control and evaluation unit 14. Sensors of
that kind can be in particular position sensors, acceleration
sensors, sensors for recording a surface ECG or blood pressure
sensors. The measurement data recorded by the sensors pass into the
evaluation logic means 32, in the form of control values. It is
also possible for one or more sensors to be already fixedly
integrated into the control and evaluation unit 14 (input unit 47).
However mobility and ease of handling of the specific control and
evaluation unit 14 are to the fore in terms of implementation.
[0057] The external control and evaluation unit 14 further includes
the autarchically runnable evaluation logic means 32 which monitors
and adjusts control of the implant 12 in dependence on the
telemetrically communicated data of the implant 12 and control
values which are discussed in greater detail hereinafter. For that
purpose the control and evaluation unit 14 has a memory 48
organized in matrix-like manner. The memory 48 can be produced
using common semiconductor technology or can be implemented at
least in parts in software form. Such an evaluation logic means 32
also includes functional components such as a processor unit for
data processing, working memories and further electronic elements
which for example permit communication with the input units 44, 45,
46, 47, the telemetry unit 16 and the sensor means 28. In practice
the functional components which serve to carry the invention into
effect are in part embodied in software form and inseparably
interwoven with the rest of the control and evaluation structure.
Electronic systems of that kind have long been known and vary
considerably in their design as a consequence of technological
progress so that a more detailed description will not be set forth
here. An energy source (not shown) is required to supply the
necessary operating voltage. A rechargeable accumulator for example
serves for that purpose.
[0058] FIG. 2 diagrammatically shows the mode of operation of an
autarchically runnable evaluation logic means 32 of the control and
evaluation unit 14. For that purpose the evaluation logic means 32
has the complex central matrix in the memory 48, into which pass
the transmitted data D.sub.im of the implant 12 and the control
values SG. A time signal t is also brought into play by way of the
clock and timer unit for co-ordination in respect of time. The
control values SG can be systematically subdivided into
time-dependent control values SG.sub.t and event-dependent control
values SG.sub.ev.
[0059] The time-dependent control values SG.sub.t include inter
alia parameters for monitoring tasks which compel at
predeterminable time intervals:
[0060] routine checking of the entire control logic means 30 of the
implant 12 or sub-regions of the control logic means,
[0061] routine checking of the entire control logic means 30 of the
implant 12 or sub-regions of the control logic means as a
consequence of an input effected by the patient, and
[0062] routine checking of the entire control logic means 30 of the
implant 12 or sub-regions of the control logic means as a result of
a presetting by means of suitable peripheral devices.
[0063] Control routines of that kind on the part of the evaluation
logic means 32 are intended to ensure trouble-free operation of the
implant 12 over long periods of time.
[0064] Under certain circumstances it is appropriate to provide
that event-dependent control values SG.sub.ev pass into the matrix
of the evaluation logic means 32. In that respect event-dependent
control values SG.sub.ev which fall to be considered are in
particular parameters for monitoring and adjusting tasks,
which:
[0065] are inputted by the patient by way of the first input unit
44, are predetermined by means of suitable peripheral devices by
way of the second input unit 46, or
[0066] which are ascertained by means of suitable sensors by way of
the input units 45, 47.
[0067] The time- and event-dependent control values SG.sub.t,
SG.sub.ev pass in combined form as control values SG into the
matrix. They are used together with the data D.sub.im of the
implant 12 for ascertaining the control sequences SS and control
parameters SP for monitoring and adjusting tasks to be
performed.
[0068] In this sense the term control sequence SS is used to denote
a programmed chain of commands, the execution of which leads to the
presetting of given control parameters SP for adjusting members
present in the implant control system. The control parameters SP
are accordingly ascertained on the spot. If the control parameters
SP were already ascertained in the evaluation and control unit 14
and transmitted telemetrically to the implant 12, transmission can
be effected directly to the adjusting members of the implant 12. In
that way it is possible to forego storing the control sequence SS
in the implant 12.
[0069] The evaluation logic means 32 includes an expert system ES
which on a patient-individual basis assesses all monitoring and
adjusting tasks for intracardial cardiac therapy. The expert system
ES serves to divide the control sequences SS on which the
monitoring and adjusting tasks are based into internal control
sequences SS.sub.in for the implant 12 and external control
sequences SS.sub.ex for the external evaluation and control unit
14. That is intended on the one hand to shorten a duration of data
transmission, by a reduction in the amount of data to be exchanged.
In addition, only the control sequences SS which are actually
necessary for autarchic runnability are to be stored in the implant
12. That saves on memory space and reduces the level of energy
consumption for those sequences are now consequently only executed
in the evaluation and control unit 14. The control parameters
resulting therefrom are then transmitted telemetrically.
[0070] The internal control sequences SS.sub.in include the
stimulation and diagnosis sequences which are absolutely necessary
for control of the stimulation function or diagnosis of given
cardiac events. If for example the patient suffers from normotopic
tachycardia of the right atrium without other stimulation
disturbances, there is no need to predetermine ventricular control
sequences. It is only if more detailed evaluation in the evaluation
and control unit 14 indicates that there is also a meaningful need
for ventricular cardiac therapy that the necessary control
sequences SS are transmitted. Control sequences SS which are to be
installed at any event on the implant 12 obviously concern real
time-dependent stimulation and diagnostic sequences.
[0071] The internal control sequences SS.sub.in and control
parameters SP remaining after selection by the expert system ES are
additionally interlinked with weighting factors G.sub.i. On the one
hand a time interval t.sub.int in which the monitoring and
adjusting tasks are to take place is to be established on the basis
of the weighting factors G.sub.i. On the other hand it is also
possible to determine a series R of the internal control sequences
SS.sub.in and control parameters SP which are transmitted during
the interaction of the external control and evaluation unit 14 to
the implant 12, for the impending monitoring and adjusting tasks
(producing an interaction scheme 50). Thus it is appropriate to
implement resetting of the control logic means 30 prior to
monitoring thereof. In the normal situation the weighting factors
G.sub.i are so selected that the time interval tint for monitoring
and adjustment occurs when the patient is in a rest phase. In the
case of acute events, for example a diagnosed active ectopic
stimulation disturbance or as a consequence of a patient input, the
time interval tint is so predetermined that it begins immediately
after the production of the interaction scheme 50. Under some
circumstances the connection between the external control and
evaluation unit 14 and the implant 12 is maintained until
optimization of the control is concluded. Data exchange can then
take place for example one after the other.
[0072] The interaction scheme 50 includes the individual tasks
which are to be executed as a consequence of matrix evaluation for
monitoring and adjustment of the control logic means 30 of the
implant 12. The series R and the time interval t.sub.int are
established for the tasks to be performed and, as soon as there is
telemetric contact they are executed. To ensure the complex
monitoring and adjusting tasks, it can be provided that the
external control and evaluation unit 14 has an acoustic output
unit. If the period of time between the last telemetric contact has
already no longer materialized for a predetermined length of time
or if urgent tasks are to be executed in the interaction scheme 50
the patient can have attention drawn to the fact of the need to
produce the contact, by means of acoustic signals.
[0073] The above-described procedure can be used both for
monitoring and adjusting the stimulation parameters and also for
monitoring and adjusting the diagnostic parameters. Thus for
example differentiated analysis of cardiac activity may be
necessary after evaluation of the data D.sub.im transmitted by the
implant 12 in order with the information obtained in that way still
further to improve the stimulation or to check the medical
necessity therefor respectively.
1 List of references 10 arrangement 12 electromedical implant 14
external control and evaluation unit 16, 18 telemetry unit 20, 22
transmitter 24, 26 receiver 28 sensor means 30 control logic means
32 evaluation logic means 34, 36 memory unit 38 electrode 40, 42
clock and timer d44, 45, 46, 47 input units 48 matrix-type memory
50 interaction scheme D.sub.im transmitted data from the implant 12
G.sub.i weighting factor R series of the monitoring and adjusting
tasks SG control value SG.sub.t time-dependent control value
SG.sub.ev event-dependent control value SP control parameter SS
control sequence SS.sub.in internal control sequence t.sub.int time
interval for the monitoring and adjusting task
* * * * *